US4949335A - A TDM quasi-duplex system - Google Patents

A TDM quasi-duplex system Download PDF

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Publication number
US4949335A
US4949335A US07/300,673 US30067389A US4949335A US 4949335 A US4949335 A US 4949335A US 30067389 A US30067389 A US 30067389A US 4949335 A US4949335 A US 4949335A
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US
United States
Prior art keywords
voice
station
transmitting
data
during
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US07/300,673
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English (en)
Inventor
Morris A. Moore
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Motorola Solutions Inc
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Motorola Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Motorola Inc filed Critical Motorola Inc
Assigned to MOTOROLA, INC. reassignment MOTOROLA, INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: MOORE, MORRIS A.
Priority to US07/300,673 priority Critical patent/US4949335A/en
Priority to CA002004023A priority patent/CA2004023C/en
Priority to FI913490A priority patent/FI913490A7/fi
Priority to EP19900903291 priority patent/EP0486494A4/en
Priority to JP2503505A priority patent/JPH04504191A/ja
Priority to PCT/US1989/005831 priority patent/WO1990008435A1/en
Priority to AU50989/90A priority patent/AU623751B2/en
Priority to KR1019900702045A priority patent/KR930011965B1/ko
Publication of US4949335A publication Critical patent/US4949335A/en
Application granted granted Critical
Priority to DK129291A priority patent/DK129291A/da
Priority to NO912722A priority patent/NO912722D0/no
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/16—Time-division multiplex systems in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
    • H04B1/40—Circuits
    • H04B1/54—Circuits using the same frequency for two directions of communication

Definitions

  • Time division multiplexing of voice and data onto a single channel is known to provide full-duplex radio operation. Typically, however, this requires at least two time slots for a radio to transmit half the time and to receive at half the time. While effective, this practice wastes spectrum since, in ordinary conversations, the talker usually receives only brief feedback responses (or acknowledgements) during his or her transmissions.
  • the primary feature of full-duplex communications is provided while conserving spectrum and without undue complexity.
  • a talker transmits while a listener receivers until a command (interrupt) code is transmitted by the listener. After appropriate signalling, the talker and listener changes roles and the original talker now listens.
  • the time allocated for voice transmission is greater than the time allocateed for receiving data for system synchronization or commands to maximize speech capacity throughput.
  • FIG. 1 is a block diagram of a communication system utilizing a TDM Quasi-Duplex System in accordance with the present invention.
  • FIG. 2 is a block diagram of either radio of FIG. 1.
  • FIGS. 3a-m are timing diagrams illustrating the operation of the system of FIG. 1.
  • a two-way radio (or station) 10 includes a transmitter 12, a receiver 14, a controller 20, and an antenna switch 18.
  • the transmitter 12 and receiver 14 are selecetively connected to an antenna 16 via the switch 18.
  • a manually operated key 31 coupled to one input of the controller 20, or a voice operated key 29 coupled to one input of the transmitter 12 selectively operates the controller 20.
  • the radio 10 communicates with a second radio (or station) 22 having an antenna 24.
  • the radio 22 may be identical to the radio 10 and may be connected to the antenna 24 as by an antenna switch 18 operated by a controller.
  • the controller 20, may include a microcomputer, which controls the operation of the transmitter 12, the receiver 14, and the switch 18.
  • FIG. 2 illustrates a block diagram of the radio 10 (or 22).
  • the transmitter 12 comprises a microphone 28, an analog to digital (A/D) converter 32, a transmitter buffer 34, a digital to analog (D/A) converter 35, a modulator 36, and a power amplifier 38.
  • the microphone 28 is coupled, via the A/D converter 32, to the controller 20, which controls the input to the transmitter buffer 34.
  • the ouput of the transmitter buffer 34 is fed into the controller 20, which regulates the input to the D/A converter 35.
  • the output of the D/A 35 is fed into the modulator 36, which is connected to the power amplifier 38.
  • the controller 20 also connects to one input of the modulator 36, and to the lower amplifier 38 to gate the modulator bursts on and off.
  • the controller 20 is coupled to and controls the switch 18.
  • the output of the power amplifier 38 is connected to the switch 18 for application to the antenna 16.
  • the receiver 14 typically comprises a front end 39, an analog to digital (A/D) converter 41, a receiver buffer 42, a digital to analog (D/A) converter 44, and a speaker 46.
  • the front end 39 is connected, via the analog to digital (A/D) converter 41, to the controller 20, which controls the input to the receiver buffer 42.
  • the output of the receiver buffer 42 is applied to one input of the controller 20 for digitall compression before application to the input of the D/A converter 44, which in turn is connected to the speaker 46.
  • the controller 20 also couples to the front end 39.
  • audio energy impressed upon the microphone 28 is digitized at normal speed (32) and buffered in the transmitter buffer 34.
  • information is retrieved from the transmit buffer 34 at a rate exceeding that of which it was stored.
  • the duration and timing of the slots are defined in accordance with any suitable TDM protocol.
  • the controller 20 forwards this information to the modulator 36, via the D/A converter 35, and the modulated information is broadcast via the power amplifier 38 and the antenna 16, after application of the switch 18.
  • received audio is sampled in the A/D converter 41 and stored at the higher rate in the receiver buffer 42.
  • the contents of the buffer 42 are applied via the D/A at normal speed to the speaker to generate speaker audio.
  • speech samples from an A/D converter would be processed continuously by a speech encoder (if required to reduce the speech information rate) and stored in a transmit buffer.
  • speech data would be retrieved from the transmit buffer and transmitted at the channel rate (greater than the speech information rate). For example, if the speech information rate was 9600 BPS, a channel transmission rate of 12000 BPS would allow for four fifths of a frame to be split between transmission from talker to listener and one fifth for the sync data transmission from listener to talker and the transmit/receive gaps required for switching as is known in the art.
  • speech data would be written into the receive buffer at the transmission rate during the receive burst and read from the buffer continuously to provide input to the speech decoder which in turn would provide normal speed voice to the speaker circuits.
  • the transmit key 31 Connected to the input of the controller 20 is the transmit key 31.
  • This may comprise a push-to-talk (PTT) switch as is commonly used with a radio, and the key 31 and microphone may be provided as a single unit.
  • the transmit key may be a voice operated relay (VOX) 29 coupled to the output of the A/D converter 32.
  • VOX voice operated relay
  • Conventional voice activated transmit systems often loose the initial portion of the first utterance.
  • this invention overcomes this problem since the mike audio is sampled and buffered by 32 and 34 respectively, as soon as the information is outputted at the mike 28.
  • a pointer inside the controller 20 could be "backed up" at the beginning of the voice prior to initiating voice transmission, thereby avoiding loss of speech due to the detect delay in the receiver. Since the VOX delay time is known, it may be compensated by retrieving the speech samples starting from this known time ahead of the VOX activation.
  • FIGS. 3a-m The sequence of operations just described is illustrated in FIGS. 3a-m wherein a radio frequency communication channel 50 having a conventional bandwidth is apportioned into substantially larger voice slots 52 than data slots 54 to achieve Time Division Multiplexing (TDM) of voice and data on a single channel. Gaps (or guards bands) 56 between the slots are reserved for the proper operation of the switch 18.
  • TDM Time Division Multiplexing
  • the ID of the listener's radio to be called, 22, will be repeatedly transmitted in the voice slots 58 and 78.
  • the protocol is illustrated for talker and listener together and separately for clarification.
  • the called unit 22 detects the address and begins acquiring synchronization adequate for TDM. When synchronization has been achieved, the called unit 22 sends a data burst designated as SYNC in data slots 62 and 82. Detection of SYNC by the calling unit 10 signals the start of voice conversation between the talker 10 and the listener 22.
  • the talker transmits and the listener receives voice during the voice slots 52 and 83, while the talker receives and the listener transmits data in the data slots 54 and 74.
  • the listener 22 transmits a command, referred to as the turnaround request code (TREQ) in the data slots 64 and 84 by manually (or vocally) activating the key 31 (or 29) as indicated.
  • the talker 10 detects TREQ 64 and 84, it acknowledges and transmits an ACK word in the first portion of the former voice slots 66 and 86.
  • the reception of TREQ 64 and 84 by the talker 10 overrides any further voice transmission and forces the talker into the role of the "new listener". To become the talker once more, key 31 must be released and re-activated.
  • the previous listener 22 now is the “new talker” that will transmit voice from unit 22 to unit 10 in the subsequent voice slots 68 and 88, and the previous talker 10 now is the “new listener” who will transmit the SYNC word in the subsequent data slots 72 and 92 to maintain TDM synchronization.
  • TDMA Time Division Multiple Access

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Bidirectional Digital Transmission (AREA)
  • Time-Division Multiplex Systems (AREA)
  • Radio Relay Systems (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
US07/300,673 1989-01-23 1989-01-23 A TDM quasi-duplex system Expired - Fee Related US4949335A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
US07/300,673 US4949335A (en) 1989-01-23 1989-01-23 A TDM quasi-duplex system
CA002004023A CA2004023C (en) 1989-01-23 1989-11-28 Tdm quasi-duplex system
AU50989/90A AU623751B2 (en) 1989-01-23 1989-12-26 A tdm quasi-duplex system
EP19900903291 EP0486494A4 (en) 1989-01-23 1989-12-26 A tdm quasi-duplex system
JP2503505A JPH04504191A (ja) 1989-01-23 1989-12-26 Ｔｄｍ準２重システム
PCT/US1989/005831 WO1990008435A1 (en) 1989-01-23 1989-12-26 A tdm quasi-duplex system
FI913490A FI913490A7 (fi) 1989-01-23 1989-12-26 Aikajakolimitetty näennäisesti kaksisuuntainen järjestelmä
KR1019900702045A KR930011965B1 (ko) 1989-01-23 1989-12-26 시분할 멀티플렉싱 의사 이중 통신 장치 및 방법
DK129291A DK129291A (da) 1989-01-23 1991-07-02 Tidsdelt, multiplekseret qvasi-duplex kommunikationssystem
NO912722A NO912722D0 (no) 1989-01-23 1991-07-11 Framgangsmaate og anordning for kommunikasjon av et talesignal.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US07/300,673 US4949335A (en) 1989-01-23 1989-01-23 A TDM quasi-duplex system

Publications (1)

Publication Number Publication Date
US4949335A true US4949335A (en) 1990-08-14

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Family Applications (1)

Application Number Title Priority Date Filing Date
US07/300,673 Expired - Fee Related US4949335A (en) 1989-01-23 1989-01-23 A TDM quasi-duplex system

Country Status (9)

Country Link
US (1) US4949335A (da)
EP (1) EP0486494A4 (da)
JP (1) JPH04504191A (da)
KR (1) KR930011965B1 (da)
AU (1) AU623751B2 (da)
CA (1) CA2004023C (da)
DK (1) DK129291A (da)
FI (1) FI913490A7 (da)
WO (1) WO1990008435A1 (da)

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991009481A1 (en) * 1989-12-18 1991-06-27 Motorola, Inc. Quasi-duplex radio system using bidirectional hole extension protocol
WO1991013498A1 (en) * 1990-02-28 1991-09-05 Motorola, Inc. Hole placement and fill system based on category selection
WO1992000634A1 (en) * 1990-06-22 1992-01-09 Motorola, Inc. Full duplex/half duplex power radio
US5170490A (en) * 1990-09-28 1992-12-08 Motorola, Inc. Radio functions due to voice compression
US5228026A (en) * 1989-01-27 1993-07-13 British Telecommunications Public Limited Company Technique for time-division duplex cordless telecommunication
US5263083A (en) * 1990-12-10 1993-11-16 Rolm Company Method and apparatus for sharing speakerphone processor among multiple users
US5420851A (en) * 1993-11-24 1995-05-30 At&T Corp. Method of multiple access
US5442635A (en) * 1989-11-03 1995-08-15 Telefonaktiebolaget Lm Ericsson Method for dividing a frame structure in a mobile station
US5448762A (en) * 1991-03-07 1995-09-05 Telefonaktiebolaget Lm Ericsson Method and apparatus for mobile radio communications having switched dual frequency synthesizers
US5517504A (en) * 1994-07-29 1996-05-14 Motorola, Inc. Method and system for providing uplink/downlink collision avoidance in a wireless communication system
US5594720A (en) * 1993-11-24 1997-01-14 Lucent Technologies Inc. Multiple access cellular communication with dynamic slot allocation and reduced co-channel interferences
US5600636A (en) * 1993-09-27 1997-02-04 Nokia Telecommunications Oy Method for digital semi-duplex transmission
US5602836A (en) * 1993-11-24 1997-02-11 Lucent Technologies Inc. Multiple access cellular communication with circular interleaving and reduced dropped-packet runlengths
US5712848A (en) * 1995-12-11 1998-01-27 Wavtrace, Inc. Time division multiplex communications system including means for reducing undesired echoes resulting from circuit delays
US5734969A (en) * 1995-06-08 1998-03-31 Hitachi Denshi Kabushiki Kaisha Radio communication method and apparatus which adds an interrupt enable synchronizing signal to a compressed voice signal in place of a synchronizing A signal
US5768254A (en) * 1995-09-29 1998-06-16 Lucent Technologies Inc. Multiple access cellular communication with signal cancellation to reduce co-channel interference
US5930246A (en) * 1996-05-15 1999-07-27 Toyota Jidosha Kabushiki Kaisha Bidirectional communication system
US6172965B1 (en) * 1996-12-23 2001-01-09 Nortel Networks Limited Duplex transmission scheme
US20020163899A1 (en) * 2001-05-04 2002-11-07 Winbond Electronics Corp. Method for transmitting packet data
US6678262B1 (en) * 1997-06-24 2004-01-13 Siemens Aktiengesellschaft Method and device for radio transmission
US20130176876A1 (en) * 2012-01-06 2013-07-11 Fujitsu Mobile Communications Limited Radio communication terminal device and radio communication terminal device control method
US10842653B2 (en) 2007-09-19 2020-11-24 Ability Dynamics, Llc Vacuum system for a prosthetic foot

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2351877B (en) * 1999-06-30 2003-08-20 Motorola Ltd Digital radio for pseudo-duplex radio communication
US9232522B2 (en) * 2013-07-19 2016-01-05 Motorola Solutions, Inc. Full duplex direct mode individual and group calling using adjacent time slots in a TDMA system

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Publication number Priority date Publication date Assignee Title
US3098124A (en) * 1958-10-13 1963-07-16 Charles B Fisher Multiplex telephony
US3202764A (en) * 1953-09-22 1965-08-24 Itt Transmission systems
US3311704A (en) * 1963-06-28 1967-03-28 Ibm Voice-data multiplexing system for transmitting data during pauses in the voice signals
US3529088A (en) * 1967-05-02 1970-09-15 Werner Hauer Multiplex voice and data transmission system
US3943444A (en) * 1973-12-21 1976-03-09 Telefonaktiebolaget L M Ericsson Procedure to watch several radio channels at radio communication
US4037158A (en) * 1974-10-07 1977-07-19 Motorola, Inc. Two-way FM radio system operating on a single channel and providing simulated duplex operation
US4476558A (en) * 1982-07-29 1984-10-09 Northern Telecom Limited Time compression multiplex digital transmission system
US4644105A (en) * 1985-03-25 1987-02-17 P.T.I., Inc. Mobile telephone controller switch
US4715059A (en) * 1985-11-07 1987-12-22 Luma Telecom, Inc. Conversational video phone
US4750169A (en) * 1985-03-12 1988-06-07 Pacific Bell Telephone system and method for transmitting digital information
US4754450A (en) * 1986-03-25 1988-06-28 Motorola, Inc. TDM communication system for efficient spectrum utilization
US4774704A (en) * 1984-10-16 1988-09-27 La Telephonie Industrielle Et Commerciale Telic Alcatel Interface circuit for connecting a digital equipment to a time multiplex link
US4839923A (en) * 1986-12-12 1989-06-13 Motorola, Inc. Method and apparatus for time companding an analog signal

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DE2338846C3 (de) * 1973-07-31 1979-03-15 Standard Elektrik Lorenz Ag, 7000 Stuttgart Sprachübertragungssystem mit einem Übertragungskanal, bei dem die Verständigung zwischen zwei Teilnehmern in beiden Richtungen möglich ist
DE2340136C1 (de) * 1973-08-08 1978-04-27 Siemens Ag Funkuebertragungssystem
GB2151436A (en) * 1983-12-09 1985-07-17 Philips Electronic Associated Duplex speech transmission method and a system therefor
GB8418935D0 (en) * 1984-07-25 1984-08-30 Racal Res Ltd Duplex communications

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Publication number Priority date Publication date Assignee Title
US3202764A (en) * 1953-09-22 1965-08-24 Itt Transmission systems
US3098124A (en) * 1958-10-13 1963-07-16 Charles B Fisher Multiplex telephony
US3311704A (en) * 1963-06-28 1967-03-28 Ibm Voice-data multiplexing system for transmitting data during pauses in the voice signals
US3529088A (en) * 1967-05-02 1970-09-15 Werner Hauer Multiplex voice and data transmission system
US3943444A (en) * 1973-12-21 1976-03-09 Telefonaktiebolaget L M Ericsson Procedure to watch several radio channels at radio communication
US4037158A (en) * 1974-10-07 1977-07-19 Motorola, Inc. Two-way FM radio system operating on a single channel and providing simulated duplex operation
US4476558A (en) * 1982-07-29 1984-10-09 Northern Telecom Limited Time compression multiplex digital transmission system
US4774704A (en) * 1984-10-16 1988-09-27 La Telephonie Industrielle Et Commerciale Telic Alcatel Interface circuit for connecting a digital equipment to a time multiplex link
US4750169A (en) * 1985-03-12 1988-06-07 Pacific Bell Telephone system and method for transmitting digital information
US4644105A (en) * 1985-03-25 1987-02-17 P.T.I., Inc. Mobile telephone controller switch
US4715059A (en) * 1985-11-07 1987-12-22 Luma Telecom, Inc. Conversational video phone
US4754450A (en) * 1986-03-25 1988-06-28 Motorola, Inc. TDM communication system for efficient spectrum utilization
US4839923A (en) * 1986-12-12 1989-06-13 Motorola, Inc. Method and apparatus for time companding an analog signal

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5228026A (en) * 1989-01-27 1993-07-13 British Telecommunications Public Limited Company Technique for time-division duplex cordless telecommunication
US5442635A (en) * 1989-11-03 1995-08-15 Telefonaktiebolaget Lm Ericsson Method for dividing a frame structure in a mobile station
WO1991009481A1 (en) * 1989-12-18 1991-06-27 Motorola, Inc. Quasi-duplex radio system using bidirectional hole extension protocol
US5091906A (en) * 1989-12-18 1992-02-25 Motorola, Inc. Quasi-duplex radio system using bi-directional hole extension
WO1991013498A1 (en) * 1990-02-28 1991-09-05 Motorola, Inc. Hole placement and fill system based on category selection
US5095540A (en) * 1990-02-28 1992-03-10 Motorola, Inc. Hole placement and fill system based on category selection
WO1992000634A1 (en) * 1990-06-22 1992-01-09 Motorola, Inc. Full duplex/half duplex power radio
US5170490A (en) * 1990-09-28 1992-12-08 Motorola, Inc. Radio functions due to voice compression
US5263083A (en) * 1990-12-10 1993-11-16 Rolm Company Method and apparatus for sharing speakerphone processor among multiple users
US5448762A (en) * 1991-03-07 1995-09-05 Telefonaktiebolaget Lm Ericsson Method and apparatus for mobile radio communications having switched dual frequency synthesizers
US5600636A (en) * 1993-09-27 1997-02-04 Nokia Telecommunications Oy Method for digital semi-duplex transmission
US5594720A (en) * 1993-11-24 1997-01-14 Lucent Technologies Inc. Multiple access cellular communication with dynamic slot allocation and reduced co-channel interferences
US5420851A (en) * 1993-11-24 1995-05-30 At&T Corp. Method of multiple access
US5602836A (en) * 1993-11-24 1997-02-11 Lucent Technologies Inc. Multiple access cellular communication with circular interleaving and reduced dropped-packet runlengths
US5517504A (en) * 1994-07-29 1996-05-14 Motorola, Inc. Method and system for providing uplink/downlink collision avoidance in a wireless communication system
US5734969A (en) * 1995-06-08 1998-03-31 Hitachi Denshi Kabushiki Kaisha Radio communication method and apparatus which adds an interrupt enable synchronizing signal to a compressed voice signal in place of a synchronizing A signal
US5768254A (en) * 1995-09-29 1998-06-16 Lucent Technologies Inc. Multiple access cellular communication with signal cancellation to reduce co-channel interference
US5712848A (en) * 1995-12-11 1998-01-27 Wavtrace, Inc. Time division multiplex communications system including means for reducing undesired echoes resulting from circuit delays
US5930246A (en) * 1996-05-15 1999-07-27 Toyota Jidosha Kabushiki Kaisha Bidirectional communication system
US6172965B1 (en) * 1996-12-23 2001-01-09 Nortel Networks Limited Duplex transmission scheme
US6678262B1 (en) * 1997-06-24 2004-01-13 Siemens Aktiengesellschaft Method and device for radio transmission
US20020163899A1 (en) * 2001-05-04 2002-11-07 Winbond Electronics Corp. Method for transmitting packet data
US10842653B2 (en) 2007-09-19 2020-11-24 Ability Dynamics, Llc Vacuum system for a prosthetic foot
US20130176876A1 (en) * 2012-01-06 2013-07-11 Fujitsu Mobile Communications Limited Radio communication terminal device and radio communication terminal device control method

Also Published As

Publication number Publication date
AU623751B2 (en) 1992-05-21
KR930011965B1 (ko) 1993-12-23
AU5098990A (en) 1990-08-13
KR910700574A (ko) 1991-03-15
JPH04504191A (ja) 1992-07-23
FI913490A0 (fi) 1991-07-19
DK129291D0 (da) 1991-07-02
CA2004023A1 (en) 1990-07-23
EP0486494A1 (en) 1992-05-27
DK129291A (da) 1991-07-02
FI913490A7 (fi) 1991-07-19
CA2004023C (en) 1993-10-12
EP0486494A4 (en) 1992-08-26
WO1990008435A1 (en) 1990-07-26

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